Waterbomb (balloon) base folding instructions
The waterbomb base, sometimes called a balloon base, is a common base fold in origami. If you're unfamiliar with the very basic origami folds, check out the first article in this series before continuing, Origami Paper Folding Instructions - a Guide to the Most Common Origami Folds.
A waterbomb base is the starting point for many more complex origami models, so it's worth familiarizing yourself with the process. You'll run across this base used in many flower and animal origami folding instructions.
In this example, we're creating a waterbomb base with the colored side of the paper on the outside. If you need the colored side of the paper to end up on the inside of your model, just start step 1 with your paper turned white side up instead. You can stock up on origami paper here.
Origami waterbomb base step-by-step
1. Start with your paper colored side up. Make a vertical valley fold, unfold, make a horizontal valley fold and unfold once more. Now turn the paper over so the white side is facing up. The squiggly arrow between fig.1 and fig.2 is a universal origami symbol used to represent flipping the paper over, you'll see that a lot.
2. Make two diagonal valley folds, one at a time and unfolding after each, similar to step 1. You should now be left with your original square shape, complete with 4 creases meeting in the exact center of the square. If the creases do not meet in the center the end product will be untidy, so you're probably better off trying it again.
3. Carefully push the left and right sides of the paper towards the center. This works best if you use one finger in the center of each side, pushing both at the same time. All of those folds we made in earlier steps should allow the paper to collapse fairly naturally into the final shape, but take it slowly at first and be sure no extra creases are being formed as these can affect your end product.
Note: This is a common technique in origami, making what may seem like multiple pointless folds at first just to create creases which make subsequent steps much easier.
4. Smooth down the creases, the 4 points of the base should be as neat as possible since in many origami patterns these will end up forming prominent features such as petals or wings.
When the base is completely flattened you should be unable to see any of the white side of the paper sticking out. The left and right tips should also sit exactly on top of one another so the whole thing looks like one triangle as in fig.6. A common problem with this base for beginners is that one slightly inaccurate fold in the first two steps results in one side of the finished base being crooked as in fig.5.
In origami, accuracy is everything. Practise until you're able to get this perfect and you'll be ready to move onto something a bit more involved. Next up in the series, a proper animal folding tutorial.